SNESSetLagPreconditionerPersists#

Set whether or not the preconditioner lagging persists through multiple nonlinear solves

Synopsis#

#include "petscsnes.h"  
PetscErrorCode SNESSetLagPreconditionerPersists(SNES snes, PetscBool flg)

Logically Collective

Input Parameters#

  • snes - the SNES context

  • flg - preconditioner lagging persists if true

Options Database Keys#

  • -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves

  • -snes_lag_jacobian <- 2,1,2,…> - sets the lag

  • -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves

  • -snes_lag_preconditioner <- 2,1,2,…> - sets the lag

Notes#

Normally when SNESSetLagPreconditioner() is used, the preconditioner is always rebuilt at the beginning of each new nonlinear solve, this removes that.

This is useful both for nonlinear preconditioning, where it’s appropriate to have the preconditioner be stale by several solves, and for implicit time-stepping, where preconditioner lagging in the inner nonlinear solve over several timesteps may present huge efficiency gains.

See Also#

SNES: Nonlinear Solvers, SNES, SNESSetLagJacobianPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetNPC(), SNESSetLagPreconditioner()

Level#

developer

Location#

src/snes/interface/snes.c

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Index of all SNES routines
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Index of all manual pages